Hold-down guard mechanism for trimming presses



Jan. 30, 1951 J. D. FOLEY HOLD-DOWN GUARD MECHANISM FOR TRIMMING PRESSESFiled Jan. 24, 1948 INVENTOR. LIUHN D. FOLEY ATTORNEY.

Patented Jan. 30, 1951 UNITED STATES PATENT OFFICE HOLD-DOWN GUARD-MECHANISM FOR TRIMMING PRESSES John D..Foley, Westport, Conn assignor toThe H. O. Canfield '00:, Bridgeport, Conn., a-corporation ofConnecticutv Application J anuary.-24, 1948, Serial No; 4,2011.

- 1 claim. I

The present invention relates to a holddownguard mechanism for trimmingpresses, andhas for-an object to provide a.-mechanism of. this characterof relatively simple and inexpensive construction, and which will'beautomatic in operation as to power actuation so that it does not dependupon the volition or judgement of the.

operator of the press to perform-its actuating function.

The guard mechanism ofthe inventionis especially adapted for cooperativeincorporation in a trimming press of the type which trims molded.articles from a sheet or'strip of molded rubber. or the like, andwherein the flexibleenature. of'

such material is such that. the operator. must holdthe. material.relatively closeto .the. die and punch ofthe. press,v so as to. properlyposition the articleto betrimmedwithinthe. die. With. this requirementin .viewit is a further object of."

the invention to. provide. a. guard' mechanism which will effectuallyprevent positioning of the fingers of the operator inthepathoffthepunchwhile at the. same time permittingthe material to be held in closeproximity, to the punchand" die. It is further. proposed to providexaguard mechanism having aguard elementadaptedto act as a holding meansfor the materialto be trimmed; ,so as to firml retain it upon the diepreparatory to engagement oil the. die by the:

punch.

A further object is to provide a guard mecha-. nism having means forautomatically causing the actuation of the. power. means for driving thepunch; and particularly to provide a precision electric switch of themicro type; which adapted'to operate withinvery closelimits, so" thatthe punch. cannot be operated until the guard is in an exactpredetermined position in relation to thedie.andthework... Anotherobject is to provide a guard'mechanism particularly adaptedforcooperation;withqaw solenoid operated trimming press, the: microswitch,,

forming part of the mechanism, being so connected as to directly openandclosethe electric circuit of; the solenoid, and. resulting in a fast-z.

operating press without an unduelag betweenthe operation of'the guardmechanismand the;punch actuating solenoid.

With the above and other objects in view, an embodiment of the inventionis. shown in the ac-. companying drawings, and this embodimentiwill be.hereinafter more fully described with refer: ence. thereto, and theinvention. will be fi'nally point'ediout in the claim.

"Inthedraw-ings:

Fig. 1 is a side elevationof'a trimming press embodying the invention,the dot-and-dash linesv indicating the position of the guard mechanisminits-operative position, as well as the position of the article to betrimmed.

Fig. 2 is a front elevation.

Fig. 3 is a -horizontal sectional plan view taken along the line 3-3 ofFig. 1.

Similar reference characters indicate corresponding parts throughout theseveralfigures of the drawings.

Referring to the drawings, the trimming press, according to theillustrated exemplary embodiment. of the. invention, comprisesv ahorizontal table or bed Iii, upon: which there is rigidly securedavertical cylindrical post H, having ad.-

justably: mounted thereonfor vertical adjust-- ment abearing head l2,secured in-its position... ofadjustmentby means of a clam-ping bolt l3.-providedrin .therearward split portion I4 of the.

head.

In theforwardly projecting end of the head there is provided avertically disposed bearing bushing. I5 for supporting the punch drivingshaft, as will presently more fully appear. In-

termediate post Hand the bearing bushing "5,, the. bearing. head isprovided with a transverse vertical shoulder l6 and a transverse recessIT,

avertically disposed platel8 being engagedat.

its lower end in the recess Hand rigidly secured by screws I9 to theshoulder 16. Upon the forward side of the plate l 8.there is secured abearing block 20 having a bearing bushing 2i therein. in axial alignmentwith the bearing bushing. l5...

and which in cooperation therewith provides a relatively long bearingsupport for the punch. drivingshaft.

Inspaced relationabove the bearing block 20.

there. is secured uponthe. forward face. of'the;.

plate 18 asol'enoid unit 22 having avertically movable plunger. armature23, the winding. of." the coil of the solenoid being such as to drivethe armature downwardly when it is energized.

A punch driving shaft' 2A is engaged for vertical movement in thebearing bushings. l5 and .2 l

andis provided near itsupper endwith a collar. 25," between which and,the bearing blockv 20' thereisprovid'ed a helical'compression spring26;.

normally-forcing the shaft upwardly. At its upper endathe shaft isprovided with a transverse.

semi-cylindrical groove 21, engaged by a cross.-

shaft '28 providedat'thelower end of the. plunger.

23, so that upon down movement of the plunger.

the..shaft.is.pressed downwardly, the spring returning.;.-the.shaft..and'jplunger. to their raisedpgisiti. when theisolenoidis..de.-energized;

. Wit 1 -a=verticalsocket29 in the lower-endof the shaft 24' there isengaged the punch 33 secured in place by a set screw 3!, and which isadapted to cooperate with a die 32 secured upon the table l9. Thesurface of this die surround.- ing its cutting edge is of truncated coneshape for the purpose of providing clearance space for the operatorsfingers, as will hereinafter more fully appear.

Anelectric switch 33 of the micro type is secured at the upper end ofthe plate I8 upon its rearward side, and is provided with an actuatingpin 34 for engagement by the guard mechanism, as will presently morefull appear. This switch is connected in the circuit of the solenoid, so

that the solenoid is energized and de-energized in the respective closedand open positions of the switch.

The safety mechanism comprises a U-shaped band member 35 engaged aboutthe forward end of the bearing head [2 and secured at its side by meansof screws 33, the leg portions or" the band projecting rearwardly fromthe bearing head and being provided in rearwardly spaced relationthereto with a-transverse shaft 37, upon the pro jecting ends of whichthere is pivotally mounted a U-shaped lever 38. The lever extendsforwardly at each side of the bearing head and is provided in theforward end of each of its side legs with a slot 39, for cooperationwith the vertically movable guard assembly, as will presently more fullyappear.

At each side of the bearing head, in transverse alignment with the axisof the punch actuating shaft, there is secured upon the band member 35by means of screws 40 a bearing block 4|, having a vertical bearingpassage 12 therein. In the bearing blocks 4! there are engaged forvertical sliding movement slide rods 33, threaded at their lower endsand screwed into the upper flattened end portions 44' of the side arms45 provided at each side of the tubular guard member 36. The guardmember is axially aligned with the punch 30, and is normally disposed inits raised position between the lower end of the punch and the die 32,being sufiiciently spaced above the die to permit placing of thematerial to be trimmed upon the die. At the upper end of each of therods 43 there is provided a forked head portion 41, engaged by theforward end of one of the side legs of the lever 38, and provided with across pin 48 engaged in the slot 39 of the lever.

The lever 38 is normally maintained in its raised position by means ofhelical expansion springs 49 connected between studs e upon each of theside legs of the lever and studs 5i provided at each side of the plateI8. Downward movement is imparted to the lever by means of pull rods 52,connected to each of the side legs of the lever by means of studs 53,these pull rods extending downwardly through passages 54 in the bed Itto a cross-head 55, to the central part of which there is secured a pullrod 55, connected at its lower end to an operating pedal 5'! connectedby a hinge 58 to the floor. The pedal is normally held raised throughthe action of the springs 4'9. Upon pressing the pedal downwardly thelever 38 is swung downwardly to bring the guard member downwardly intoguarding relation with the die 32 and the work engaged thereon, as shownby the dot-and-dash lines in Fig. l.

A yoke member 59 is secured at its lower end to the side legs of thelever 38, and upon its upper mounted contact screw 60 held in itsadjusted position by retaining nuts 6 l and 62, this contact screwadapted as the lever 38 is swung downwardly to engage and depress thepin 34 of the micro switch 33, as shown by the dot-and-dash lines,Fig. 1. The micro switch is so positioned with respect to the contactscrew that the circuit 53 of the solenoid is closed at the exactpredetermined point when the guard member engages the work piece topress it against the die, whereupon the downward operation of theplunger presses the punch downwardly into engagement with the die. Itwill thus be seen that if a finger of the operator is disposed in thepath of the punch, the guard member cannot be brought downwardly to thepoint where the micro switch will be actuated. The tapering of thesurface of the die permits the fingers to be placed in very closeproximity to the cutting edge of the die without danger of being hit bythe punch.

I have illustrated and described a preferred and satisfactory embodimentof the invention, but it will be understood that changes may be madetherein, within the spirit and scope thereof, as defined in the appendedclaim.

What is claimed is:

In a press holddoWn-guard mechanism, a fixed tool part, a verticallymovable tool part, power means for vertically moving said movable toolpart downwardly and upwardly respectively into and out of relation tosaid fixed tool part, a holddown-guard element comprising a tubular wallsurrounding said movable tool part and vertically I movable downwardlyand upwardly in parallel' relation to the movement of said movable toolpart respectively into and out of guarding relation to said fixed toolpart, said fixed tool part having an opening for engagement by saidmovable tool part and having an annular downwardly tapered wallsurrounding said opening and disposed directly beneath the tubular wallof said holddown-guard element, means normally urging saidholddown-guard element into raised position, manually operable actuatingmeans connected to said holddown-guard element to move it downwardlyinto holding relation with the upper side of the work engaged upon saidfixed tool part independently of the movement of said movable tool partand said power means, means for controlling the operation of said powermeans, and means carried by said manually op: erable means for operatingsaid last named means at a predetermined point of movement of saidholddown-guard element.

, JOHN D. FOLEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name r Date 618,065 Dicks Jan. 24, 1899779,427 Jessop Jan. 10, 1905 915.438 Hornor Mar. 16, 1909 1,179,477Thomas Apr. 18, 1916 1,551,447 Wilde Aug. 25, 1925 1,684,296 BrodskySept. 11, 1928 2,236,730 MacBlane Apr. 1, 1941 2,315,151 Booth Mar. '30,1943" 2,348,566 Papazian May 9; 1944""-

